Pneumatic control system for quick clamping of cornice brake tools

ABSTRACT

The quick tool clamping system relates to a cornice brake in which there are rows of punches and dies and modular units consisting of intermediates and clamping jaws for the intermediates and jaws for clamping punches, with the latter being operated by actuators driven by pneumatic cylinders, and is characterized in that: a) in the intermediates and the jaws clamping the intermediates to the cursor of the press there are channels for feeding of the fluid under pressure to the actuator cylinder; b) said channels lead to at least one hole opening onto the opposing surfaces of each pair of intermediates and associated clamping jaw; and c) on at least one of the two opposing surfaces of each pair of intermediates and associated clamping jaw the associated hole opens onto a groove running horizontally in the surface and positioned at the same level as the hole opening onto the opposing surface, and in the circuit for supplying the fluid under pressure to every intermediate a valve is inserted designed to intercept the flow of fluid towards the intermediate.  
     In accordance with a variation the groove running horizontally is missing and the holes opening onto the opposing surfaces of each pair of intermediates and associated clamping jaw are mutually opposed.

THE FIELD OF THE INVENTION

[0001] The present invention relates to a pneumatic control system forquick clamping, release, withdrawal and change of cornice brake tools.

BACKGROUND OF THE INVENTION

[0002] For cold working of sheet metal work pieces by bending, pressestermed ‘cornice brakes’ using appropriately shaped pairs of tools(punches and dies) are commonly used. In these machines the variousprocessing steps require frequent replacement or lateral shifting of thetools. These operations are usually performed either by completelymanual procedures which require long pauses for loosening and thenclamping of numerous modular unit bolts for clamping the tools, or withthe aid of clamping and unclamping systems for the modular units withautomatic hydraulic or pneumatic control. When the punch tip which isopposite the bending axis is not positioned on the axis of the punchtang which clamps the punch to the press cursor the use of adaptor orintermediate modules termed ‘extensions’ or ‘intermediates’ which act aspunch lengthening members is required.

[0003] Known pneumatic control systems for quick clamping of tools aredescribed in European patent no. 0 754 506, in Italian patentapplication no. MI98A 001084 and in sales pamphlet ‘Quick tool change oncornice brakes’ of the Teda s.r.l. company with seat in Piacenza, Italy.

[0004] These known systems call for modular tool clamping and unclampingunits comprising punch clamping jaws and actuators driven by pneumaticcylinder fed through channels in the body of the intermediates andthrough tubes running between the intermediates of each pair ofintermediates placed side by side. These tubes are capable of runningwith compressed air seal within the above cavities so as to allowlimited lateral traversing of the intermediates along the front of thebrake before they are clamped.

[0005] These systems do not give rise to particular problems if the workto be performed on the brake does not require removal of theintermediates. But if this removal is required it is necessary to removetogether with the intermediates each pair of the above mentioned tubesinserted in the intermediates removed and then install a tube ofsufficient length in place of each intermediate and each pair of tubesremoved. These removal and replacement operations cause loss of time.

SUMMARY OF THE INVENTION

[0006] The general purpose of the present invention is to produce apneumatic system for quick tool clamping in cornice brakes which wouldnot require tubes for supply of fluid under pressure running between theintermediates and which would allow quick removal of the intermediates.Another purpose of the system is to allow installation of punches notrequiring intermediates or installation of intermediates for manualclamping the punch tang on the intermediate.

[0007] The quick tool clamping system of the present invention relatesto a cornice brake in which there are rows of punches and dies andmodular units consisting of intermediates and clamping jaws for theintermediates and jaws for clamping punches, with the latter beingoperated by actuators driven by pneumatic cylinders, and ischaracterized in that:

[0008] a) in the intermediates and the jaws clamping the intermediatesto the cursor of the press there are channels for feeding of the fluidunder pressure to the actuator cylinder,

[0009] b) said channels lead to at least one hole opening onto theopposing surfaces of each pair of intermediates and associated clampingjaw,

[0010] c) on at least one of the two opposing surfaces of each pair ofintermediates and associated clamping jaw the associated hole opens ontoa groove running horizontally in the surface and positioned at the samelevel as the hole opening onto the opposing surface, and

[0011] d) in the circuit for supplying the fluid under pressure to everyintermediate a valve is inserted designed to intercept the flow of fluidtowards the intermediate.

[0012] In accordance with a variation the groove running horizontally ismissing and the holes opening onto the opposing surfaces of each pair ofintermediates and associated clamping jaw are mutually opposed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] To better explain the innovative principles of the presentinvention and its advantages there is described below with the aid ofthe annexed drawings possible embodiments thereof by way of non-limitingexample.

[0014] In the drawings:

[0015]FIG. 1 shows a perspective view of work stations of a cornicebrake of known type with pneumatic quick clamping of tools,

[0016]FIG. 2 shows a cross section view of a work station (upper part)of FIG. 1,

[0017]FIG. 3 shows the work station of FIG. 1 without the upper tools ofthe middle station,

[0018]FIG. 4 shows a cross section view of an intermediate and of thepunch and intermediate clamping jaws in accordance with an embodiment ofthe quick clamping system of the present invention,

[0019]FIG. 5 shows a view from the right of the jaw 14 of FIG. 4,

[0020]FIG. 5a shows an enlarged view of a detail of FIG. 5,

[0021]FIG. 6 shows a view from the left of the intermediate 13 and thejaw 29 of FIG. 4, and

[0022] FIGS. 7 to 9 a show cross section views of the components 5, 13and 14 of FIG. 4 in accordance with two variants of the valve 22 of thesame FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023]FIGS. 1, 2 and 3 relate to a known quick tool clamping andunclamping system with pneumatic control of the type described in theabove mentioned documents.

[0024] In FIG. 1 the different parts represent:

[0025]1. dies

[0026]2. punches

[0027]3. intermediates

[0028]4. manual clamping jaws for clamping the intermediates to thecursor 5 of the press,

[0029]6. pneumatic control jaws for clamping the punch tang to theintermediates,

[0030]7. tubes (shown in broken lines) for supply of fluid underpressure, running between the intermediates, and

[0031]8. hole for supply fluid under pressure in the intermediates.

[0032]FIG. 2 (corresponding to FIG. 4 of the above mentioned Italianpatent application no. MI98A001084) shows a cross section of thepneumatic punch clamping system of FIG. 1.

[0033] In accordance with this system the fluid under pressure, forexample air, controls the pneumatic cylinder 9 (made in the intermediatebody) through the channel 8′ and the duct 10. When the fluid comes underpressure the piston 11 of the pneumatic cylinder moves towards the rightand cause clamping of the jaw 6′ against the tang of the punch 2′.

[0034]FIG. 3 shows the case in which the press of FIG. 1 requiresremoval of a punch (the center one in the FIG) and associatedintermediate to allow special bending. In this event it is necessary toremove, together with the middle intermediate, the two tubes supplyingfluid under pressure and connecting the intermediate to those beside itand then replace the two tubes with a single tube 12 to restore theconnection of the intermediates 3′ and 3″.

[0035]FIGS. 4, 5 and 6 show a pneumatic system for quick clamping andunclamping, withdrawal and change of tools in accordance with thepresent invention.

[0036] This system displays the following main features:

[0037] a) each intermediate 13 and in the associated jaw 14 for clampingthe intermediate to the cursor 5 of the press there are channels 15 and16 for feeding the fluid under pressure to the actuator cylinder 9controlling clamping of the tang 18 of the punch against theintermediate,

[0038] b) the above mentioned channels lead to a respective hole 19, 20opening onto the opposing surface of the intermediate and of theclamping jaw,

[0039] c) on one of the two opposing surfaces and specifically on thejaw surface the associated hole 20 opens onto a groove 21 runninghorizontally in the surface and positioned at the same level as the hole19 opening onto the opposing intermediate surface, and

[0040] d) in the supply circuit of the fluid under pressure towards eachintermediate a valve 22 designed to intercept the flow of fluid towardsthe intermediate is inserted.

[0041] As shown in FIG. 5 (view from the right of the jaw 14) the systemused for supplying fluid under pressure in the channel 16 calls for aserial supply of the clamping jaws 14 of the intermediates through tubes23 connecting together each side-by-side pair of jaws. This type ofsupply is not binding however because a non-serial but independentsupply for the channel 16 of each jaw can be provided in a quite obviousmanner.

[0042] In the same FIG reference number 24 designates the holes in whichare inserted the screws 24′ for clamping the jaw, and 25 designates twoholes in which springs tending to withdraw the jaw from the cursor 5 arehoused.

[0043]FIGS. 5 and 5a (the latter showing an enlarged view of the part ofFIG. 5 involved with the straight groove 21) also show on the internalsurface of the jaw an annular groove in which is inserted a seal 26(rubber or other similar material) designed to ensure sealing of thefluid under pressure when the jaw 14 is clamped against theintermediate.

[0044]FIG. 6 (showing a view from the left of the intermediate 13 andthe jaw 29) shows the path followed by the channel 15 for carrying fluidunder pressure (entering from the hole 19) up to the chamber 27 of thepneumatic cylinder 9.

[0045] In the same FIG, 28 designates the holes for insertion of thepins 28′ which allow clamping (with a horizontally pivoted movement) ofthe jaw 29.

[0046] FIGS. 7 to 9 a show the usefulness of the groove 21 and twodifferent ways of providing the valve 22 of FIG. 4.

[0047] The version of FIGS. 7 and 7a (the latter being an enlarged viewof the part of FIG. 7 surrounded by a circle in broken lines) concernsan embodiment of the valve 22 of the manually operated type. In this FIGthe valve is shown open. It comprises a cylindrical chamber 37 coaxialwith the axis of the hole 20 and having a diameter greater than that ofthe hole. It also comprises an elastic seal ring 30 located on thebottom of the chamber and a small cylinder 31 fastened near the end of ascrew 32 so as to be pressable against the ring 30 or withdrawabletherefrom by screwing or unscrewing the screw.

[0048]FIG. 7a shows the cylinder 31 spaced from the ring 30 so as toallow the discharge of the fluid under pressure from the hole 20 intothe groove 21, the hole 19 and the channel 15, and the resultingclamping of the jaw 29 (FIG. 4).

[0049] To ensure said clamping it is not necessary for the hole 19 to beexactly opposite the lower edge of the hole 20 but it is sufficient thatit be opposite any point of the groove 21 (see FIGS. 5 and Sa).

[0050] This makes it possible to allocate the intermediate on the frontof the press to different positions within a range of variability equalto the length of the groove 21.

[0051] To use the press under operating conditions similar to those ofFIG. 3, i.e. with one or more intermediates uninstalled, it issufficient to manually tighten the screw 32 until it compresses the sealring 30 by means of the cylinder 31. By so doing, the stream of liquidunder pressure towards the hole 20 is interrupted, the jaw 14 can beloosened manually and the intermediate 13 can be withdrawn withoutcausing leakage of the fluid under pressure from the hole 20 during thesubsequent starting up of the press.

[0052] The closed condition of the valve 22 not only allows withdrawalof the intermediate but allows use of conventional intermediates(without internal channel) or punches not requiring intermediates.Indeed, in these cases the jaw 14 behaves like a conventional jaw andoperation under pneumatic control of the other positions of the press isnot affected because closing of the hole 20 prevents falling of thefluid pressure.

[0053]FIGS. 8 and 8a show a second version of the valve 32 andspecifically a valve with automatic operation.

[0054] The valve is again structured like that of FIGS. 7 and 7a exceptthat the cylinder 31′ is free to traverse in the chamber 37 and ispressed rightward by a spring 40. The rod 41 on which the cylinder 31′is fastened has its right end which in closed position of the valve(cylinder 31′ pressed by the spring against the ring 30) emerges fromthe hole 20, while the same end when it is brought level with the outletedge of the hole puts the valve in open position (FIG. 8a).

[0055] Accordingly when the clamping screws 24′ of the jaw 14 areloosened the jaw withdraws from the intermediate 13 and the valve closesautomatically. As soon as the jaw 14 is again clamped against theintermediate 13 the end of the rod 41 is pushed within the hole 20 andthe air supply is automatically restored.

[0056] This automatic opening and closing system of the valve 22requires use of a clever device if it is desired to use the jaw 14 forclamping conventional intermediates or punches not requiringintermediates. Indeed, in this case it is necessary to avoid operationof the valve by these tools. This can be secured by providing aprojection 42 near the seal 26 and a corresponding recess (step 43 ofFIG. 8a) in the intermediate with channel. This device has the effect ofallowing operation of the valve by the intermediates in accordance withthe present invention and of preventing operation when conventionalintermediates or punches not requiring intermediates are used. Indeed,in the latter case as illustrated in FIGS. 9 and 9a the projection 42prevents operation of the valve by the tool on which the jaw 14 isclamped and this way the valve is always in closed position.

[0057] Naturally numerous modifications, adaptations, variants andreplacements of members with others functionally equivalent can be madeto the embodiments described above by way of example without goingbeyond the scope of the claims set forth below.

[0058] Said variants could concern for example the groove 21 which couldbe replaced or accompanied by a similar groove located on theintermediate 13 and at the level of the hole 19. In addition this groovecould be missing if lateral traversing is not provided for theintermediates. Other variants could concern the cutoff valve as regardsits structural features and its position not necessarily near the hole20 or in the intermediate clamping jaw. This possibility of differentposition is valid in particular for the manually operated valve withindependent feed of each jaw.

1. Pneumatic control system for quick clamping of tools in a cornicebrake in which there are rows of punches and dies and modular unitsconsisting of intermediates, jaws for clamping the intermediates andjaws for clamping punches, with the latter being operated by actuatorsdriven by pneumatic cylinders, characterized in that: a) in theintermediates and the jaws clamping the intermediates to the cursor ofthe press there are channels for feeding of the fluid under pressure tothe actuator cylinder; b) said channels lead to at least one holeopening onto the opposing surfaces of each pair of intermediates andassociated clamping jaw; c) on at least one of the two opposing surfacesof each pair of intermediates and associated clamping jaw the associatedhole opens onto a groove running horizontally in the surface andpositioned at the same level as the hole opening onto the opposingsurface; and d) in the circuit for supplying the fluid under pressure toevery intermediate a valve is inserted designed to intercept the flow offluid towards the intermediate.
 2. Pneumatic control system for quickclamping of tools in a cornice brake in which there are rows of punchesand dies and modular units consisting of intermediates, jaws forclamping the intermediates and jaws for clamping punches, with thelatter being operated by actuators driven by pneumatic cylinders,characterized in that: a) in the intermediates and the jaws clamping theintermediates to the cursor of the press there are channels for feedingof the fluid under pressure to the actuator cylinder; b) said channelslead to two holes mutually opposed opening onto the opposing surfaces ofeach pair of intermediates and associated clamping jaw; and c) in thesupply circuit for fluid under pressure toward each intermediate isinserted a valve designed to intercept the flow of fluid towards theintermediate.
 3. System in accordance with claim 1 characterized in thatthe above mentioned groove running horizontally is surrounded by asecond groove in which a seal of elastic material is seated, designed toensure seal of the fluid under pressure when the intermediate andassociated clamping jaw are clamped together.
 4. System in accordancewith claim 1 or 2 characterized in that the above mentioned valve ismanually operated.
 5. System in accordance with claim 1 or 2characterized in that the above mentioned valve is operatedautomatically and is put in closing or opening condition when the jaw inwhich it is located is clamped to or respectively is shifted from theassociated intermediate.
 6. System in accordance with claim 5characterized in that in each intermediate clamping jaw there is aprojection on the surface designed to close against the intermediate,designed to be inserted upon clamping in a corresponding recess on theopposing surface of the intermediate so as to prevent opening of theabove mentioned valve when the jaw is clamped against tools not havingthe above mentioned recess.